The Kőszeg Mountains , sometimes called the Guns or Güns Mountains (, ), are a

mountain range A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have aris ...

in the Alpokalja area, the easternmost region of the

Alps The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia. ...

. The territory of the range is shared between

Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...

and

Hungary Hungary is a landlocked country in Central Europe. Spanning much of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia and ...

. Geologically, the mountains represent a Penninic window, formed from metamorphic rocks transformed about 28–31 million years ago and uplifted between 15–18 million years ago. The landscape features a main north-south ridge with multiple east-west

tributary A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...

ridges, creating a distinctive pattern of parallel valleys shaped by streams flowing eastward toward the Gyöngyös. The mountain range's

hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydro ...

includes a network of permanent and intermittent streams that have shaped the terrain through

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

and occasional flash floods. The varied habitats of the Kőszeg Mountains support rich

biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...

, including dozens of species of soil-dwelling enchytraeid worms and orthopteran insects ( grasshoppers and

cricket Cricket is a Bat-and-ball games, bat-and-ball game played between two Sports team, teams of eleven players on a cricket field, field, at the centre of which is a cricket pitch, pitch with a wicket at each end, each comprising two Bail (cr ...

s), with distinct species assemblages corresponding to different vegetation types from wet

meadow A meadow ( ) is an open habitat or field, vegetated by grasses, herbs, and other non- woody plants. Trees or shrubs may sparsely populate meadows, as long as they maintain an open character. Meadows can occur naturally under favourable con ...

s to xeric grasslands.

Geology and topography

The Kőszeg Mountains represent the easternmost extension of the

and have a distinctive geological composition. They formed from rocks that underwent metamorphic transformation about 28–31 million years ago (mya), with the mountains themselves being uplifted between 15.1–18.5 mya. The range is primarily composed of various types of

phyllite Phyllite ( ) is a type of foliation (geology), foliated metamorphic rock formed from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation.Stephen Marshak ''Essentials of Geology'', 3rd ed. I ...

(a shiny foliated metamorphic rock) including quartz phyllite, calcareous phyllite, and black lead phyllite, along with metaconglomerate (transformed sedimentary rock consisting of rounded pebbles cemented together). Geologically, the Kőszeg Mountains belong to the Penninic unit of the Alpine system, and are specifically part of what geologists call the Rechnitz window group, representing the easternmost outcrop of this unit. The mountains show evidence of multiple metamorphic events, particularly a low-temperature/high-pressure blueschist facies Alpine event that was later overprinted by a medium-pressure greenschist facies metamorphism. While the age of the earlier high-pressure event remains undetermined, K–Ar dating on muscovite from the mountains' phyllites indicates that the later medium-pressure metamorphic event occurred approximately 28–31 mya during the meso-Alpine period. The landscape of the Kőszeg Mountains on the Hungarian side features one main ridge running north-south, with multiple smaller ridges branching off to the east. These east-west

ridges formed as streams carved valleys while retreating westward from the Gyöngyös stream, which flows along the eastern edge of the mountains. This process created a series of parallel valleys separated by these smaller ridges. The elevation of the mountains is relatively modest, with the main ridge reaching heights between 400–500 metres above sea level. The town of Kőszeg sits at the eastern foot of the northern portion of the main ridge, partly on the plain of the Gyöngyös Stream (at elevations of 272–275 metres) and partly on the gentle slopes rising toward the mountains (elevations between 275–400 metres). This sloping surface represents what geologists call a "residual pediment" – a gently inclined erosional surface at the foot of the mountains that has been shaped by streams depositing sediment to form a fan-like structure known as a " bajada" in the mountain foreland. The mountains feature several distinctive topographical features, including flat-topped

ridge A ridge is a long, narrow, elevated geomorphologic landform, structural feature, or a combination of both separated from the surrounding terrain by steep sides. The sides of a ridge slope away from a narrow top, the crest or ridgecrest, wi ...

s formed by stream capture (where one stream diverts the flow of another), interesting rock formations exposed by

, and step-like features on valley slopes. The southern part of the range has a particular structure of rock layers tilting toward the south, which influences how erosion shapes the landscape.

Hydrology

The water systems of the Kőszeg Mountains are characterised by a network of streams and springs that have played a significant role in shaping the landscape. The Gyöngyös stream is the main watercourse along the eastern boundary of the mountains, collecting water from numerous smaller streams that flow eastward from the main ridge. These mountain streams, though relatively small, are powerful shapers of the landscape, especially during periods of heavy rainfall. The area experiences both permanent streams with year-round flow and intermittent streams that appear primarily during rainfall events or snowmelt. Springs in the region include the Szénégető spring and the Szikla spring, which contribute to the local water system. The pattern of water flow in the mountains follows the

topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the landforms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sci ...

, with streams generally flowing eastward from the main ridge toward the Gyöngyös Stream. This drainage pattern has created a series of parallel valleys separated by smaller ridges. The valleys themselves often feature stepped profiles, where alternating flat sections and steeper drops reflect the underlying geological structure and the erosive power of the water. Research conducted after intensive rainfall events in 2009 and 2010 demonstrated how quickly these mountain streams can transform during flash floods. During these events, channels deepened by as much as 70 centimetres in some areas, and stream paths changed significantly. The power of these water flows became evident as they transported large amounts of

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

, creating alluvial fans (fan-shaped deposits of sediment) both within channels and at valley mouths. The hydrology of the area has direct implications for nearby settlements, particularly the town of Kőszeg, which sits at the eastern foot of the mountains. During heavy rainfall events, the town has experienced flooding and sediment deposition as water and soil material flow down from the mountain slopes along stream valleys. Researchers note that while the exhumation mechanism and history of the Kőszeg-Rechnitz Window are well understood, detailed quantitative measurements of the pressure-temperature conditions during the mountains' formation and precise dating of the oldest high-pressure metamorphic event are still lacking for the Hungarian portion of these formations.

Biodiversity

The Kőszeg Mountains host a diverse array of

flora Flora (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...

and

fauna Fauna (: faunae or faunas) is all of the animal life present in a particular region or time. The corresponding terms for plants and fungi are ''flora'' and '' funga'', respectively. Flora, fauna, funga and other forms of life are collectively ...

adapted to the region's particular climatic conditions. A 2017 study documented a rich enchytraeid fauna (small white soil-dwelling annelid worms) comprising 59

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

across 15

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

, along with two other annelid species. The mountain range's

shows similarities to that of the Rax mountains in the northern Alps of Austria, with the presence of several subalpine and alpine species. Some species found in the Kőszeg Mountains, such as '' Fridericia discifera'', '' F. raxiensis'', and '' Euenchytraeus clarae'', are considered possible relicts from the Ice Age. The region's varied habitats support different species compositions, with the most species-rich sites being an alder carr (

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

forest) at a creekside near Paprét (33 species) and a mesophile montane hay meadow at Steirer Houses (27 species). The Kőszeg Mountains support rich insect diversity, with a wide variety of orthopteran ( grasshopper and

) species adapted to the region's diverse habitats. A 2002 study documented 40 Orthoptera species distributed across the mountain range's various microhabitats. These species form distinct assemblages corresponding to five main habitat types: xeric grasslands, humid and mesic meadows, mountain grasslands, clear-cuts, and ecotone zones. The research revealed that habitat characteristics — particularly vegetation height, humidity levels, and total plant coverage — significantly influence species distribution. Vegetation structural diversity (or patchiness) correlates positively with grasshopper species richness, highlighting the importance of habitat heterogeneity for biodiversity conservation. Some orthopteran species serve as biological indicators for specific environmental conditions, with certain species showing strong preferences for either moist or dry conditions. The most diverse orthopteran communities were found in transitions between habitat types.

Geology and topography

Hydrology

Biodiversity

References

See also